Conventionally, an assembled battery having a plurality of cells disposed in a stack and spacer members sandwiched between adjacent cells is known (for example, refer to JP-A-2013-206666). In such an assembled battery, a cooling circulation passage for supplying cooling air into gaps between cells is formed in order to cool each of the cells.
In the assembled battery, the spacer member has dividing parts extending in a stacking direction of the cells and connecting parts extending in parallel with surfaces of the cells. Therefore, the cooling circulation passage is formed between adjacent cells by the partition parts and the connecting parts of the spacer member and the surfaces of the cells.
Accordingly, in the assembled battery, each cell is cooled by cooling air supplied to the cooling circulation passage.
Incidentally, cells may include an outer case (can) for accommodating a power generating element, the outer case having an opening end and a body part thinner than the opening end (for example, refer to WO 99/025036). In this cell, since a wall thickness at the opening end is thicker than that at the body part, a temperature in an inside of the opening end is unlikely to drop more than a temperature in an inside of the body part does when the opening end and the body part are exposed to cooling air. Therefore, a cooling efficiency of the cell may decrease. Such a phenomenon is not limited to a case of cooling the cell. The phenomenon may also occur in a case of heating the cell.